Methylene phosphonates of glycidyl reacted polyalkylene polyamines and use in scale and chelation

ABSTRACT

Methylene phosphonates of glycidyl reacted polyalkylene polyamines and to uses therefor, particularly as scale inhibitors, chelating agents, etc.

United States n 1 Quinlan 1 Dec. 16, I975 ME'I'IIYLENE l-nosi-llomm-zsor GLYCIDYL memo I'OLYA'LKYLENE POLYAMINES AND use In SCALE ANDCIIELA'HON I'driek M. M, Webster Groves; Mo.

Assignee: Petrol: Corporation, St. Louis,

Filed: Dec. II, 1973 Appl. No.: 423,671

name us. Appialion om Division of Ser. No. l29.955, March 3l. l97l. Pat.No. 3,799,893.

inventor:

US. Cl. 210/58; 252/855; 252/82; 252/180; 252/545; 252/DIG. ll; 252/DIG.17 Int. Cl. C02]! 5/06 M of Search 252ll80, 82, 545. 8.55 B. 252/DIG.ll, DIG. I7

Primary Examiner-Benjamin R. Padgett Assistant Examiner-Deborah L. KyleAttorney, Agent, or Firm--Sidney B. Ring; Hyman F. Glass [57] ABSTRACTMethylene phosphonates of glycidyl reacted polyalkylene polyamines andto uses therefor, particularly as scale inhibitors, chelating agents.etc.

ammo-wa s METHYLENE PHOSPHONATES OF GLYCIDYL REACTED POLYALKYLENEPOLYAMINES AND USE IN SCALE AND CHELATION This application is a divisionof Ser. No. 129,955 filed Mar. 3], l97l, now US. Pat. No. 3,799,893,patented Mar. 26, I974.

Most commercial water contains alkaline earth metal cations, such ascalcium, barium, magnesium, etc., and anions such as bicarbonate,carbonate, sulfate, oxalate, phosphate, silicate, fluoride, etc. Whencombinations of these anions and cations are present in concentrationswhich exceed the solubility of their reaction products, precipitatesform until their product solubility concentrations are no longerexceeded. For example, when the concentrations of calcium ion andcarbonate ion exceed the solubility of the calcium carbonate reactionproduct, a solid phase of calcium carbonate will form as a precipitate.

Solubility product concentrations are exceeded for various reasons, suchas evaporation of the water phase, change in pH, pressure ortemperature, and the introduction of additional ions which can forminsoluble compounds with the ions already present in the solution.

As these reaction products precipitate on the surfaces of thewater-carrying system, they form scale. The scale prevents effectiveheat transfer, interferes with fluid flow, facilitates corrosiveprocesses, and harbors bacteria. Scale is an expensive problem in manyindustrial water systems, causing delays and shutdowns for cleaning andremoval.

Scale-forming compounds can be prevented from precipitating byinactivating their cations with chelating or sequestering agents, sothat the solubility of their reaction products is not exceeded.Generally, this approach requires many times as much chelating orsequestering agent as cation present, and the use of large amounts oftreating agent is seldom desirable or economical.

More than years ago it was discovered that certain inorganicpolyphosphates would prevent such precipitation when added in amountsfar less than the concentrations needed for sequestering or chelating.See, for example, Hatch and Rice, Industrial Engineering Chemistry,"vol. 31, p. 51, at 53; Reitemeier and Buchrer, Joumal of PhysicalChemistry, vol. 44, No. 5, p. 535 at 536 (may 1940 Pink and RichardsonUS. Pat. No. 2,358,222; and Hatch US. Pat. No. 2,539,305. When aprecipitation inhibitor is present in a potentially scale-forming systemat a markedly lower concentration than that required for sequesteringthe scale forming cation, it is said to be present in thresh oldamounts. Generally, sequestering takes place at a weight ratio ofthreshold active compound to scaleforming cation component of greaterthan about ten to one, and threshold inhibition generally takes place ata weight ratio of threshold active compound to scaleforming cationcomponent of less than about 0.5 to I.

The threshold concentration range can be demonstrated in the followingmanner. When a typical scaleforming solution containing the cation of arelatively insoluble compound is added to a solution containing theanion of the relatively insoluble compound and a very small amount of athreshold active inhibitor, the relatively insoluble compound will notprecipitate even when its normal equilibrium concentration has beenexceeded. If more of the threshold active compound is added, aconcentration is reached where turbidity or a precipitate of uncertaincomposition results. As still more of the threshold active compound isadded, the solution again becomes clear. This is due to the fact thatthreshold active compounds in hibh concentrations also act assequestering agents, although sequestering agents are not necessarilythreshold" compounds. Thus, there is an intermediate zone between thehigh concentrations at which threshold active compounds sequester thecations of relatively insoluble compounds and the low concentrations atwhich they act as threshold inhibitors. Therefore, one could also definethreshold" concentrations as all concentrations of threshold activecompounds below that concentration at which this turbid zone orprecipitate is formed. Generally the threshold active compound will beused in a weight ratio of the compound to the cation component of thescale-forming salts which does not exceed about I.

The polyphosphates are generally effective threshold inhibitors for manyscale-forming compounds at temperatures below F. But after prolongedperiods at higher temperatures, they lose some of their effectiveness.Moreover, in an acid solution, they revert to ineffective or lesseffective compounds.

A compound that has sequestering powers does not predictably havethreshold inhibiting properties. For example, ethylene diaminetetracetic acid salts are powerful sequesterants but have no thresholdactivities.

I have now discovered a process for inhibiting scale such as calcium,barium and magnesium carbonate, sulfate, silicate, etc., scale whichcomprises employing threshold amounts of methylene phosphonates ofglycidyl reacted polyalkylene polyamines.

The amines employed herein are polyalkylenepolyamines, for example, ofthe formula wherein n is an integer for example I to 25 or more, such as2 10, but preferably 2 5, etc., and A is an alkylene group (CI-I,)-where m is 2 10 or more, but preferably ethylene or propylene.

One or more of the hydrogens on the CH group may be substituted forexample, by such groups as alkyl groups, for example, methyl, ethyl,etc. Examples of A include iii ill, iH H,, H; EH H- l-I-, H- iH-, HCH,H, etc.

H H H;

These include the following:

NH,CH,CH,NH.

CH; (I: H NH H-Cl-hN H, etc.

The polyalkylene polyamines are reacted with glycidyl compounds of thegeneral formulas:

hydrocarbon glycidyl ether H 2) R-C-CH,

glycidyl hydrocarbon, hydrocarbon olefin oxide, or a hydrocarbon epoxidewhere R is a substituted group such as a hydrocarbon group, for example,alkyl, aryl, alkaryl, aralkyl, cycloalkyl, etc.

ln the preferred embodiment R is a hydrocarbon group having about 4 32carbons, as about 4 to 22 carbons, but preferrably from about 4 to 18carbons where the hydrocarbon is alkyl or aryl.

The substituted polyamines suitable as intermediates for the preparationof the compounds of this invention may be prepared by the slow additionof an olefin oxide or glycidyl epoxide to the warmed polyamine accordingto the following general type reactions:

The following table illustrates glycidyl compounds suitable for use inthis invention.

Table l Glycidyl Compounds Ex. C lQ-fl-L-Z l C,H,,OCH 2. C.;H,;,OCH,

3. O-O-CH 4. nonyl -O-CH H i a 5. -CH

CH 3 Cl O 2 crc 3 6. -OCH CH -O-CH 7. RO-CH, (Procter and Gamble EpoxideNo. 7)

R is mixed C,. hydrocarbon 8. ROCH, (Procter and Gamble Epoxide No. 8)

R is a mixed C hydrocarbon 9. ROCH,-- (Procter and Gamble Epoxide No.45]

R is a mixed C hydrocarbon R is a mixed C hydrocarbon RO-CH, (ADM Nedoxlll4) R is a mixed C hydrocarbon ROCH (Union Carbide Olefin oxide l4l6)R is a mixed C l6 hydrocarbon The amount of glycidyl compound reactedwill depend on the particular polyamine, the number of methylenephosphonates desired in the final product, the system in which it isemployed, etc. In general, less than all of the nitrogen-bondedhydrogens are reacted so as to leave hydrogens which are capable ofbeing phosphomethylolated. Reaction with the glycidyl compound iscarried out in the conventional manner.

The glycidyl reaction product of polyalkylene polyamine is thenphosphomethylolated. This is preferably carried out by the Mannich typereaction as illustrated in the following reaction where -NH indicates atleast one reactive group on the polyamine.

The Mannich reaction is quite exothermic and initial cooling willgenerally be required. Once the reaction is well under way, heat may berequired to maintain refluxing conditions. While the reaction willproceed at temperatures over a wide range, i.e., from 80 to 150C, it ispreferred that the temperatures of the reaction medium be maintained atthe refluxing temperatures. The reaction is preferably conducted atatmospheric pressure, although sub-atmospheric and 5 moles or more ofphosphonic acid can be used per mole equivalent of amine, although themost preferred molar equivalent ratios of formaldehyde: phosphonic acid:amine is 1: 1:1. Excess formaldehyde and/or phosphonic acid functionessentially as solvents, and thus there is no real upper limit on theamount of these materials which may be used, per mole equivalent ofamine, although such excess amounts naturally add to the cost of thefinal product and are therefore not preferred. The preferred molarequivalent ratios are is to 2 moles each of the formaldehyde andphosphonic acid per mole equivalent of amine.

The Mannich reaction will proceed in the presence or the absence ofsolvents. The reaction may be carried out as a liquid-phase reaction inthe absence of solvents or diluents, but is preferred that the reactionbe carried out in an aqueous solution containing from about 40 to about50% of the reaction monomers. Preferred conditions for the Mannichreaction include the use of formaldehyde based on the molar equivalentamount of the amine compound, the use of a stoichiometric amount ofphosphonic acid based on the molar equivalent amount of amine (e.g., onthe amine active hydrogen content), refluxing conditions and a pH ofless than 2 and preferably less than 1.

Although formaldehyde is preferred, other aldehydes or ketones may beemployed in place of formaldehyde such as those of the formula where Rand R are hydrogen, or a hydrocarbon group such as alkyl, i.e., methyl,ethyl, propyl, butyl, etc., aryl, i.e., phenyl, alkylphenyl, phenalkyl,etc., cycloalkyl, i.e., cyclohexyl, etc.

The compound can also be prepared by a modified Mannich reaction byemploying a chloromethylene phosphonate -continued Thus, thecompositions of this invention are prepared b l. Reacting glycidylcompounds with alkylene polyamine to the desired degree while leavingsome unreacted NH groups.

2. phosphomethylolating the glycidyl reaction product of the polyamineso that at least one, or all of the NH groups, or less than all of thegroups are phosphomethylolated.

The final reaction product may be summarized by the following idealizedformulas:

where n is 1 25, m x equals the sum of the valences on the polyamine(i.e., n 2) with the proviso each has a value of at least one. Whereless than all of the nitrogen-bonded hydrogens are reacted either byreaction with the glycidyl compound or phosphomethylolating they willremain as hydrogen atoms.

In general it is preferred that at least 50% and preferably at least ofthe nitrogen-bonded hydrogens of the polyamine be replaced by methylenephosphonate groups and the remainder of the nitrogen-bonded hydrogensreacted with the glycidyl compound, preferably with 1 to 2 glycidylunits per polyamine. Or, stated another way, by the formula where the Rgroups are glycidyl reaction units or where at least 50% and preferably80% of the R groups are where n, A have the meanings stated herein,i.e., n l 25, but preferably 2 5, A is alkylene preferably ethylene, andM is hydrogen or a salt moiety.

Scale formation from aqueous solutions containing an oxide variety ofscale forming compounds, such as calcium, barium and magnesiumcarbonate, sulfate, silicate, oxalates, phosphates, hydroxides,fluorides and the like are inhibited by the use of threshold amounts ofthe compositions of this invention which are effective in small amounts,such as less than ppm, and are preferably used in concentrations of lessthan 25 p.p.m.

The compounds of the present invention (e.g., the acid form of thecompounds) may be readily converted into the corresponding alkali metal,ammonium or alkaline earth metal salts by replacing at least half of thehydrogen ions in the phosphonic acid group with the appropriate ions,such as the potassium ion or ammonium or with alkaline earth metal ionswhich may be converted into the corresponding sodium salt by theaddition of sodium hydroxide. If the pH of the amine compound isadjusted to 7.0 by the addition of caustic soda, about one half of theOH radicals on the phosphorous atoms will be converted into the sodiumsalt form.

The scale inhibitors of the present invention illustrate improvedinhibiting effect at high temperatures when compared to prior artcompounds. The compounds of the present invention will inhibit thedeposition of scale-forming alkaline earth metal compounds on a surfacein contact with aqueous solution of the alkaline earth metal compoundsover a wide temperature range. Generally, the temperatures of theaqueous solution will be at least 40F., although significantly lowertemperatures will often be encountered. The preferred temperature rangefor inhibition of scale deposition is from about 130 to about 350F. Theaqueous solutions or brines requiring treatment generally contain about50 p.p.m. to about 50,000 ppm. of scale-forming salts. The compounds ofthe present invention effectively inhibit scale formation when presentin an amount of from 0.1 to about 100 ppm, and preferably 0.2 to 25 ppm.wherein the amounts of the inhibitor are based upon the total aqueoussystem. There does not appear to be a concentration below which thecompounds of the present invention are totally ineffective. A very smallamount of the scale inhibitor is effective to a correspondingly limiteddegree, and the threshold effect is obtained with less than 0.1 ppm.There is no reason to believe that this is the minimum effectiveconcentration. The scale inhibitors of the present invention areeffective in both brine, such as sea water, and acid solutions.

In the specific examples the general method of phosphomethylolation isthat disclosed in Netherlands Pat. Nos. 6407908 and 6505237 and in theJournal of Organic Chemistry, Vol. 31, No. 5, 1603-1607 (May, 1966).These references are hereby incorporated by reference.

In general, the method consists of the following: The glycidyl reactedpolyamine is slowly added with cooling to the mixture of phosphonic andhydrochloric acids. After the addition is completed, the reactionmixture is heated to 100-110C. and the aqueous formaldehyde is slowlyadded over a period of l to 1 hours while maintaining a temperature oflO-l 10. After the addition is completed, the reaction mixture is heldat reflux temperatures for l-2 additional hours. The preferred molarequivalent ratios are a 2 moles each of the fon'naldehyde and phosphonicacid per mole equivalent of amine, although the most preferred molarequivalent ratios of formaldehyde: phosphonicacid: amine is 1:1:1.

The preferred amine reactants to be used in the preparation of the aminomethylene phosphonic acids of the present invention are essentiallyglycidyl reacted polyamines. Suitable polyamines include the following:diethylene triamine, triethylene tetramine, tetraethylene pentamine,pentaethylene hexamine, ditetramethylene triamine, tritetramethylenetetramine, dihexamethylene triamine and the like. Linear polyaminemixtures that may be reacted are Amine E-lOO from Dow Chemical Company,Amine No. 1 from Jefferson Chemical Company, and Amine No. 248 from E.l. DuPont and Company, are also desirable from an economic standpoint.Other suitable amines are polyethyleneimines such as the "PH" seriesfrom Dow Chemical.

The preparation of the glycidyl reacted polyamine methylene phosphonicacids of this invention is illustrated in the following examples.

EXAMPLE 1 To a solution of 16.6 g. of phosphorous acid in 20 ml ofwater, and 22 g. of concentrated hydrochloric acid, was slowly added 24g. of the reaction product of P & G Epoxide No. 8 (1 mole) withtetraethylene-pentamine (1 mole). The solution was heated to reflux, and18 g. of 37% aqueous formaldehyde solution was added dropwise over aperiod of 1% hours. The resulting foamy solution was then held at refluxfor an additional two hours.

The acid was obtained by concentration of the reaction mixture. It was ahard brittle resin like solid that foamed in water. The calcium salt ofthe acid had good solubility in organic solvents.

EXAMPLE 2 To a solution of 16.6 g. of phosphorous acid, 17 ml. of water,and 22 g. of concentrated hydrochloric acid, was slowly added a solutionof 24 g. of the reaction product of ADM Chemical Nedox 1518 (1 mole)with diethylenetriamine (1 mole) in 50 ml. of t-butyl alcohol. Theresulting solution was heated to reflux and 18 g. of 37% aqueousformaldehyde was slowly added over a period of 1% hours. The resultingsolution was refluxed for an additional 2 hours. The acid was obtainedby concentration of the reaction mixture. It was a hard resin like solidthat foamed in water. The barium salt of the acid displayed excellentsolubility in organic solvents.

EXAMPLE 3 To a solution of 16.6 g. of phosphorous acid in 20 ml. ofwater and 22 g. of concentrated hydrochloric acid was slowly added 22.3g. of the reaction product of butyl glycidyl ether (2 moles) withtetraethylenepentamine (1 mole). The resulting solution was heated toreflux and 18 g. of 37% aqueous formaldehyde was slowly added over aperiod of 2 hours. The resulting solution was heated at reflux for anadditional 2 hours.

EXAMPLE 4 To a solution of 16.6 g. of phosphorous acid in20 ml. ofwater, and 22 g. of concentrated hydrochloric acid, was slowly added22.1 g. of the reaction product of phenyl glycidyl ether (2 moles) withtriethylenetetramine (1 mole). The resulting solution was heated toreflux and 18 g. of 37% aqueous formaldehyde was slowly added over aperiod of 2 hours. The resulting solution was further refluxed for anadditional 2 hours.

Table 11 illustrates further examples of glycidyl reacted alkylenepolyamines.

Table 11 Poly-amine (1 mole) Epoxide (moles) added to polyamine Thedegree of phosphomethylolation can be controlled by varying the molarratios of the reactants. However, for effective scale inhibition, I havefound that the maximum degree of phosphomethylolation is to bepreferred. In other words, a complete replacement of the remainingactive hydrogen atoms on the glycidyl reacted alkylene polyamines bymethylene phosphonate groups has been found to be most desirable forscale inhibition.

These methylene phosphonates are threshold active scale inhibitors atroom temperature, and are also effective at elevated temperatures. Theyalso retain their effectiveness in acid and salt solution and haveexcellent solubility in waters with high hardness content.

Calcium Scale Inhibition Test The procedure utilized to determine theeffectiveness of my scale inhibitors in regard to calcium scale is asfollows:

Several 50 ml. samples of a 0.04 sodium bicarbonate solution are placedin 100 ml. bottles. To these solutions is added the inhibitor in variousknown concentrations. 50 ml. samples of a 0.02 M CaCl solution are thenadded.

A total hardness determination is then made on the 5050 mixtureutilizing the well known Schwarzenbach titration. The samples are placedin a water bath and heated at 180F. 10 ml. samples are taken from eachbottle at 2 and 4 hour periods. These samples are filtered throughmillipore filters and the total hardness of the filtrates are determinedby titration.

Total hardness after heating 00 h,b Total hardness before heating X I lm I Table III describes the scale inhibition test results.

Table III Inhibitions of Scale Formation From A CaCO; Solution at 180F.for 4 Hours (200 p.p.m. CaCO Table III-continued lnhibitions of ScaleFormation From A CaCQ; Solution at IF. for 4 Hours [200 p.p.m. CaCO,)

Inhibitor Salt Conc. ppm Scale Inhibition USE IN THE CHELATION ORSEQUESTRATION OF METAL IONS The chelating or sequestering agents of thepresent invention are of wide utility such as when it becomes necessaryto sequester or inhibit the precipitation of metal cations from aqueoussolutions. Among their many uses are the following applications:

Soaps and detergents, textile processing, metal cleaning and scaleremoval, metal finishing and plating, rubber and plastics industry, pulpand paper industry, oilwell treatment, chelation in biological systems.

An important function of these compounds is their ability to sequesterFe. In secondary oil recovery by means of water floods, waters arefrequently mixed on the surface prior to injection. Frequently thesewaters contain amounts of Fe and H 8. If these incompatible waters aremixed, as FeS precipitate results which can plug the sand face of theinjection well. Another of their functions is to prevent formation ofgelatinous iron hydroxides in the well and in the effluent productionwaters.

To demonstrate the effectiveness of the glycidyl reacted polyaminesmethylene phosphonic acids in chelating Fe, the following test procedurewas utilized. Into a flask that contained a known concentration of thesequestering agent, and enough sodium hydroxide or hydrochloric acid togive the desired pH was placed a l00 ml. aqueous sample of ferrousammonium sulfate (20 ppm of Fe), after final pH adjustment the solutionwas allowed to remain at ambient temperatures for 48 hours. The solutionwas centrifuged for one hour to remove collodial iron hydroxide and analiquot of the supernatant solution was analyzed by atomic absorption todetermine the iron concentration.

The following table illustrates the ability of the sequestering agentsof the present invention to sequester Fe, as compared to the well knownsequestering agent tetra-sodium ethylenediamine tetrafacetate (EDTA).

Table IV pH sequestering Amount of iron Agent (ppm) Sequestered (ppm)Product Example 5 EDTA (50) (7) 7 EDTA (50) (7) Table IV-continued pHsequestering Amount of iron Agent (ppm) Sequestered (ppm) l l I50) l7)l0 2 I50) l7) l0 3 I50) l0 EDTA I50) 6) As one can observe from thepreceding table, the sequestering agents of this invention are aseffective, and in some cases superior, to EDTA when tested over a widepH range.

The sequestering agents of this invention are also quite effective insequestering other metal cations in aqueous solutions. For example, atest was conducted in which 60 ppm of the sequesterant were dissolved in100 ml. of water. The pH was adjusted to 9 and maintained there. Metalcations were added, in the following amounts, before a noticeableprecipitate was formed.

Table V Metal (ppm) Sequestered per Sequesterant 60 ppm of SequesterantProduct Example Fe 60 Example l Al lZO) Example 1 Cu (120) Example l Ni50) Example 3 Fe 60) Example 3 Al" (120) Example 3 Cu (120) Example 3 Ni60) Other heavy metals sequestered by the sequestering agents of thisinvention such as cobalt, manganese, chromium and the like.

In summary, the products of this invention are glycidyl reactedphosphomethylolated polyalkylene polyamines having at least three aminounits. Reaction is preferably carried out with a glycidyl compound ofthe formula where R had at least about 4 carbons but preferably about 4to 18 carbons. The phosphomethylolated groups, i.e.,

(or salts thereof) preferably comprise at least 50% but most preferablyat least about 80% of the available nitrogen-bonded hydrogens on thepolyamine, the remaining nitrogen-bonded hydrogens being preferablynitrogen-bonded glycidyl reacted groups. The preferred polyalkylenepolyamine has 2 such as 2 l0 nitrogen units and most preferably 2 5nitrogen units the preferred embodiment being polyethylene polyamines.These compositions are employed as scale inhibitors, chelating agents,and the like. Various modifications will be evident to those skilled inthe art.

The terms olefin oxide, epoxide," and glycidyP are used interchangeablyto describe the group. Thus alkyl glycidyl, alkyl olefin oxide orepoxide are alkyl and alkyl glycidyl ether is alkyl-OCH Other glycidylcompounds are correspondingly named.

As is quite evident, new glycidyl compounds will be constantly developedwhich could be useful in my invention. It is, therefore, not onlyimpossible to attempt a comprehensive catalogue of such compounds, butto attempt to describe the invention in its broader aspects in terms ofspecific glycidyl compound used would be too voluminous and unnecessarysince one skilled in the art could by following the description of theinvention herein select a useful glycidyl ether and react it. Toprecisely define each specific useful glycidyl compound in light of thepresent disclosure would merely call for chemical knowledge within theskill of the art in a manner analogous to a mechanical engineer whoprescribes in the construction of a machine the proper materials and theproper dimensions thereof. From the description in this specificationand with the knowledge of a chemist, one will know or deduce withconfidence the applicability of specific glycidyl compounds suitable forthis invention by applying them in the invention set forth herein. inanalogy to the case of a machine, wherein the use of certain materialsof construction or dimensions of parts would lead to no practical usefulresult, various materials will be rejected as inapplicable where otherswould be operative. I can obviously assume that no one will wish toemploy a useless glycidyl compound nor will be misled because it ispossible to misapply the teachings of the present disclosure to do so.Thus, any glycidyl compound which can be reacted with polyamine and thenphosphomethylolated can be employed.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. A process for inhibiting scale formation in aqueous systems bychelation or sequestration which comprises adding to said system amethylene phosphonate of glycidyl compound reacted polyalkylenepolyamine, said methylene phosphonate of glycidyl compound reactedpolyalkylene polyamine having nitrogenbonded methylene phosphonate unitsand nitrogenbonded glycidyl compound reacted units, said methylenephosphonate being of the formula where n is l-lOO, A is(CX where m is2-10 and X is hydrogen or alkyl, with the proviso that A is the same ordifferent when n is 2 or more, and R is a methylene phosphonate unit,glycidyl compound reacted unit or hydrogen.

2. The process of claim 1 where the nitrogen-bonded glycidyl compoundreacted unit is and R is a hydrocarbon group.

3. The process of claim 2 where n is 2-5, m is 2, and X is hydrogen.

4. The process of claim 3 where the methylene phosphonate of glycidylcompound reacted polyalkylene polyamine has the formula 7. The processof claim 2 where the nitrogen-bonded glycidyl compound reacted unit is8. The process of claim 1 where the alkylene group of the polyalkylenepolyamine is ethylene and the polyalkylene polyamine has 2-5 aminogroups.

1. A PROCESS FOR INHIBITING SCALE FORMATION IN AQUEOUS SYSTEMS BY CHELATION OR SEQUESTRATION WHICH COMPRISES ADDING TO SAID SYSTEM A METHYLENE PHOSPHONATE OF GLYCIDYL COMPOUND REACTED POLYALKYLENE POLYAMINE, SAID METHYLENE PHOSPHONATE OF GLYCIDYL COMPOUND REACTED POLYALKYLENE POLYAMINE HAVING NITROGEN-BONDED METHYLENE PHOSPHONATE UNITS AND NITROGENBONDED GLYCIDYL COMPOUND REACTED UNITS, SAID METHYLENE PHOSPHONATE BEING OF THE FORMULA (R0-)2-N-(A-N(-R0))N-R0 WHERE N IS 1-100, A IS (CX2)M WHERE M IS 2-100 AND X IS HYDROGEN OR ALKYL, WITH THE PROVISO THAT A IS THE SAME OR DIFFERENT WHEN N IS 2 OR MORE, AND R0 IS A METHYLENE PHOSPHONATE UNIT, GLYCIDYL COMPOUND REACTED UNIT OR HYDROGEN.
 2. The process of claim 1 where the nitrogen-bonded glycidyl compound reacted unit is
 3. The process of claim 2 where n is 2-5, m is 2, and X is hydrogen.
 4. The process of claim 3 where the methylene phosphonate of glycidyl compound reacted polyalkylene polyamine has the formula
 5. The process of claim 1 where the amount of scale inhibitor is from 0.1 to about 100 parts per million based upon the total aqueous system.
 6. The process of claim 2 where the nitrogen-bonded glycidyl compound reacted unit is
 7. The process of claim 2 where the nitrogen-bonded glycidyl compound reacted unit is
 8. The process of claim 1 where the alkylene group of the polyalkylene polyamine is ethylene and the polyalkylene polyamine has 2-5 amino groups. 